It should cost you very little to have a shop drain your system and reclaim the r12. The shop that did my '90 10yrs ago did it for free, simply to get the r12.

I personly had a poor experience with my r134 conversion. I found that while it cooled things off, it never made the truck that comfy on a hot humid day here in CA. On days when the temp was above 95 it barely made it tolerable, and if above 100 I did just as good to roll the windows down. Since I removed the r34 refrigerant and replaced it with Maxifridge it cools things off almost as good as the r12, it actually gets cold enough on hot 100+ days that I have to turn the fan down.

I converted my '92 to R134 about 5 or 6 years ago. I will get 38deg air out the vents on a 100deg day, as long as I'm moving over 40mph. When I slow way down or stop, the temp comes up. Not a big deal unless I'm sitting in traffic for a while. I have a very small leak and have to add a can every 12 to 18 months.....

Hey Snowtoy, what's this Maxfridge and where do you get it?

MaxiFrig is a replacement refrigerant that is compatible with both r12 and r134 oils. It runs colder and operates at a lower pressure than the r134, so it is easier on the compresor.

I posted a comparison here Maxifrig vs R12 last year. There are some links to other BB's where the different types of refrigerants are discussed. From what I understand Maxifrig is a carbon(propane) based refrigerant, which has given some people misgivings about using it in their car. However the amount of propane used is small enough that there is little to no chance of a fire being caused from a leak in the system. Furthermore, since propane has an odorant added which is easily detected by the the human nose, any leak inside the cabin should be easily detected by the occupants unlike the r134 or r12, which have little to no odor at all.

OK guys I plan on renting a pump for the weekend. Does anyone know how much oil I should put back into the system? I beleive the can I bought is a 2 oz of oil and 2 oz of r134a in a single charge can. An should I add the oil first, or after 1 can of r134a?

Thanks

Oh yeah I forgot to ask, After I get the system vacuumed down and know it has no leaks, do I leave the system under vacuum and start adding the r134a, or should I release the vacuum and the start adding the r134a? I have looked but cant find any info on this. And if anyone knows how much oil to add to a completly empty system (ie. flushed completly) let me know.

Thanks

Check the FSM sticky'd here for the '93 in that section; should give you everything, to include the oil servicing. Seems to me it's around 60cc, but DO double check.

I was able to get some info from the FSM 40-50cc for condeser, 40-50cc for evap., 20cc for drier. I drained about 60cc from the compressor, so that would give me a generous # of 6.0oz of oil total. I have a 8 oz total system charge 8oz oil and 2oz r134a. What would I do with the rest of the charge, or even tell how much is actually in the system and how much is in the can? I may be making this sound too critical, if so just let me know, as im just not familiar with this part of the truck.

Thanks for the help though.

1 leak check with nitrogen (not compressed air)

2 evacuate to 500 microns ( 1 hour will do if you dont have micron gauge)vacume pumps are not good for leak check,it only proves you can hold about 15psi or atmospheric pres.

3 add refrigerant,if it wont take the whole charge start the motor and run the comp. ( you will probably have to jump the low pres. switch out)
if I conflict with your fsm then follow fsm ,this is just a general idea